Update assembler/usage

assembler%2Fusage.md

@@ -774,3 +774,32 @@ include print "../resources/dsa/print.dsa"
 include fib "../resources/dsa/fib.dsa"
 ```
 
+## Example Programs and libraries.
+
+```dsa
+// this is a simple library to calculate the fibonacci sequence up to n, writing each value to the stack.
+
+fib_n:
+    pop ret  // pops the return address from the stack
+    pop rg0 // pops the function arg (n) from the stack
+
+    lli 0, rg1
+    lli 1, rg2
+    
+start:
+    add rg1, rg2, acc
+    push rg1
+    mov rg2, rg1
+    mov acc, rg2
+    
+    cmp rg0, zero
+    dec rg0
+    
+    jgt start
+    jmp 4, ret
+```
+
+
+
+
+